Unit 3: Energy and Momentum

Energy Objectives:1. Define work and calculate the work done by a force.2. Calculate the kinetic energy of a moving object.3. Determine the gravitational potential energy of a system.4. Calculate the power of a system.5. Apply conservation of energy to analyze energy transitions and transformations in a system.6. Analyze the relationship between work done on or by a system, and the energy gained or lost by that system.7. Use Hooke's Law to determine the elastic force on an object.Calculate a system's elastic potential energy.

Kinetic and Potential Energy

2

Potential Energy

Potential Energy (PE) is energy an object has due to its position

Gravitational potential energy (PEg) is the energy an object has because of its position in a gravitational field (height).

Note!

We know that

∆PEg = mg∆h

But we also knowFg = mg

So the formula could also be re-written as

∆PE = Fg∆h

Kinetic Energy

Kinetic energy is energy of motion.

KE = kinetic energym = massv = speed

Work-Energy Theorem

Energy Transformations- Energy can be transformed from one type to another.- You can transfer energy from one object to another by doing work (specifically kinetic energy because doing work means you’re moving the object).

Work-Energy TheoremWork done on a system by an external force changes the energy of the system. If they are asking about change in total energy, they are asking about work. [Note: Work is directly transferred to Kinetic Energy.]

Quest 20 is due Monday